1. What is the best most obvious observation from this photo that this is a pond or lake 2. What evidence is there of the abiotic factor of sunlight in this ecosystem?
3. What producer supports the food chains in this ecosystem?
4. What would this ecosystem look like if nutrias were present?
5. What type of human activity could negatively impact this ecosystem? how?

Imagine you are a student in alfred hershey and martha chase's lab in the late 1940's. you are given five test tubes with the e. coli bacteria that were infected with t2 bacteriophage that have been labeled with 32p or 35s. unfortunately, you forgot to label the tubes and are now uncertain which were 32p labeled and which were 35s labeled. you place the contents of each tube in a blender and pulse it for a few seconds to shear off the protein coats from the bacterial outer membranes. you then centrifuge the contents to seperate the protein coats and the bacterial cells. you then check for radioactivity and obtain the results shown below. which tubes contained e. coli infected with the phage labeled with 32p? select all tubes that apply.